Nature's Great Walls (8/26/12)

Yesterday was our last day in Istanbul.  Before heading to the airport my sister and I decided to take one more walk around Sultanahmet.  We went to the palace gardens of Topkapi where I learned that there is an Istanbul Museum for the History of Science and Technology in Islam.  Unfortunately we did not get to do in, since it was too early, but we did get to see a huge globe which depicted the known world as it looked in 200 A.D.

Among other thing, what I learned initially learned is that there were a lot of walls around the world.  They seemed clearly depicted all over the globe as you can see here:

10,000 unskilled workers constructed Aya Sofia in less then six years, so maybe they built walls in their spare time.  Big, huge walls across the world.  Just as I was starting to ponder the number of people it would take to build walls on that magnitude, it occurred to me that maybe those aren't great walls, but mountain ranges.

I guess mountains are natures great walls, but it's just not nearly as impressive to think something formed over thousands and thousands of years instead of having been made by hand just a few months back.